KR100419702B1 - Liquid crystal display apparatus for reducing size of display area and method of the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of reducing the size of a display screen, wherein the liquid crystal panel is divided into first and second regions, and includes two lamps corresponding to the first and second regions, respectively. In the normal display mode, both lamps are turned on to display an image in both the first and second areas of the second liquid crystal panel. In the reduced display mode, only the lamp corresponding to the first area of the liquid crystal panel is turned on, and then the first lamp is turned on. Display images only on a part of the area. Therefore, it is a very useful invention that can significantly reduce the power consumed in the lamp.

Description

Liquid crystal display apparatus for reducing size of display area and method of the same}

The present invention relates to a liquid crystal display (LCD) device, and more particularly to a liquid crystal display device capable of reducing the size of a display screen.

FIG. 1 is a view illustrating a configuration of a general TFT-LCD (Thin Film Transistor Liquid Crystal Display) device 100. Referring to FIG. 1, the liquid crystal display device 1 includes a liquid crystal panel 10 in which liquid crystal is injected between two glasses, and gate and source driving circuits 20 for driving the liquid crystal panel 10. And a driver including a timing controller 40 for generating control signals for controlling these driver circuits, and a chassis structure including a backlight unit 60. The assemblies composed of these are commonly referred to as TFT-liquid crystal display devices (or liquid crystal display devices), and the liquid crystal display device 100 is a system such as a notebook computer, a television (TV), and a monitor. Used as the device in charge of the display function.

The backlight unit 60 is composed of an inverter 62, a fluorescent lamp 64, a reflecting plate 66, and the like, and produces flat light with uniform brightness from the fluorescent lamp 64 used as a light source. The lamp 64 is largely classified into a Cold Cathode Fluorenscence Tube (CCFT) and a Hot Cathode Fluorenscence Tube (HCFT), and the reflector 66 serves to change a reflection angle of light. In addition, the liquid crystal panel 10 emits light in which white plane light incident from the backlight unit 60 passes through the pixel in response to each pixel signal voltage input from the driving circuits 20 and 30. By controlling, a color image is displayed.

2 is a block diagram illustrating a lamp driving scheme of the liquid crystal display apparatus 100 when the liquid crystal display apparatus 100 is used as a display apparatus in a portable computer or a desktop computer. Generally, portable computer or desktop computer systems are driven with direct current voltage, while lamp 64 is lit with an alternating voltage of about 1000-1500 volts. Accordingly, the liquid crystal display device 100 essentially requires an inverter 62 for converting a DC voltage into an AC voltage as shown in the drawing. In addition to the operation of converting such a DC voltage into an AC voltage, the inverter 62, as well known to those skilled in the art, has a dimming circuit therein (not shown). Is provided to perform the function of adjusting the brightness of the lamp (64).

Referring to FIG. 2, when a user inputs a brightness control command through a computer operation, the computer main body 200 generates a brightness control signal BT for adjusting the brightness to the inverter 62. When the luminance control signal BT is input from the computer main body 200, the dimmer circuit provided in the inverter 62 limits the current of the lamp 64 in response to the luminance control signal BT so that the lamp 64 is turned on. Adjust the brightness.

In the portable computer using the liquid crystal display device 100 as the display device as described above, the lamp 64 of the liquid crystal display device 100 consumes the most power among the components of the portable computer. Therefore, the conventional portable computer automatically shuts off the lamp 64 when the user does not use the computer for a predetermined time to save power when power is supplied from the battery. This method can reduce power consumption when the user is not using the computer. On the other hand, when the user is using a computer, power saving is achieved by using the above-described brightness adjustment method. However, the brightness control method also has a disadvantage in that the power consumption is still large because the lamp 64 should always be turned on when the user is using the computer.

Accordingly, the present invention has been proposed to solve the above problems, and to provide a liquid crystal display device and method that can reduce power consumption.

1 is a view for showing the configuration of a general TFT-LCD device;

2 is a block diagram for showing a lamp driving scheme of the liquid crystal display device when the liquid crystal display device is used as a display device in a portable computer or a desktop computer;

3 is a view showing the configuration of a liquid crystal display device according to a preferred embodiment of the present invention;

4 is a functional block diagram of the liquid crystal display device shown in FIG. 3;

FIG. 5 is a block diagram illustrating the backlight unit shown in FIG. 3; FIG.

FIG. 6 is a flowchart showing operations of the graphic controller and the liquid crystal display unit shown in FIG. 4 according to a user's display mode selection; FIG. And

7A and 7B are views exemplarily showing images displayed on an LCD panel according to a user's display mode selection.

※ Explanation of code for main part of drawing

300: liquid crystal display device 310: liquid crystal panel

302A: first area 302B: second area

320: gate driving circuit 330: source driving circuit

340: gradation voltage generating circuit 350: timing controller

360: backlight unit 370: power supply

362: Inverter 364, 366: Lamp

400: computer body 410: graphics controller

420: key input unit

A liquid crystal display device of the present invention for achieving the above object includes: a liquid crystal panel for displaying image signals provided from a host; Using a first lamp corresponding to the first area of the liquid crystal panel and a second lamp corresponding to the second area except for the first area of the liquid crystal panel as a light source, planar light having uniform brightness is applied to the liquid crystal panel. A backlight for providing; And a backlight driving circuit for selectively driving the first and second lamps according to a change in operating conditions.

(Example)

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 3 to 7.

3 is a view showing the configuration of a liquid crystal display device according to a preferred embodiment of the present invention. Referring to the drawings, when the configuration of the liquid crystal display device illustrated in FIG. 3 is compared with that of the liquid crystal display device 100 illustrated in FIG. 1, the backlight unit 360 may include the first and second portions of the liquid crystal panel 310. It has the same configuration as the liquid crystal display device shown in FIG. 1 except that it has two first and second lamps 364 and 366 corresponding to the regions 302A and 302B, respectively. Therefore, detailed description of the block performing the same function will be omitted to avoid overlapping description. The backlight unit 360 provides flat light having uniform brightness to the liquid crystal panel 310 using the first and second lamps 364 and 366 as light sources.

4 illustrates the liquid crystal display device illustrated in FIG. 3 as a functional block. Referring to FIG. 4, the liquid crystal display device 300 includes a liquid crystal panel 310 and a gate driving circuit 320 connected to the liquid crystal panel 310. And a source driving circuit 330, a gray voltage generator 340, a timing control circuit 350, a backlight unit 360, and a power supply unit 370.

The liquid crystal panel 310 includes a plurality of gate lines G0-Gn and a plurality of data lines (or source lines D0-Dm) perpendicularly intersecting each of the gate lines G0-Gn. It is composed. Pixels are arranged at the intersections of the gate lines G0-Gn and the data lines D0-Dm, each of which includes a thin film transistor T1 and a liquid crystal capacitor. liquid crystal capacitor (CL), and storage capacitor (CS). The gate of the thin film transistor T1 is connected to the corresponding gate line, and the source is connected to the corresponding source line. Gate driving circuit 320 is connected to each gate line G0-Gn, and source driving circuit 330 is connected to each data line D0-Dm. However, in the preferred embodiment of the present invention, the switching transistors SW1-SW2 are connected between the jth to nth gate lines Gi-Gn and the gate driving circuit 320, respectively. In addition, gates of the thin film transistors connected to the first to mth data lines D1 to Dm may be selectively connected to the gate driving circuit 320 in the 0th to ith gate lines G0-Gi. Switching transistors S3-SW4 for connection are connected. The switching transistors SW1-SW4 are NMOS transistors. The gate of the NMOS transistor is used as a control terminal for controlling the turn-on or turn-off of the transistor, which receives the selection signal SEL output from the timing controller 350 as shown in FIG. 4.

The image displayed through the liquid crystal panel 310 is obtained by a combination of three types of color filters: red (R), green (G), and blue (B), and the liquid crystal display device 300 Represents a purely red, green, blue and gray scales as well as a color image by the combination thereof. The gray voltage generator 340 is connected to the source driver circuit 33 to generate a voltage Vgray which is a reference for generating the liquid crystal driver voltage. The backlight unit 360 is connected to the liquid crystal panel 310 to provide planar light with uniform brightness to the liquid crystal panel 310. When the gate driving circuit 320 sequentially scans the pixels of the liquid crystal panel 310 by one column, the source driving circuit 330 may generate a timing controller in response to the reference voltage Vgray output from the gray voltage generator 340. A liquid crystal driving voltage is generated based on the color signal RGB input through 40, and the generated liquid crystal driving voltage is applied to the liquid crystal panel 310 every scanning. The power supply unit 370 supplies various kinds of power required for the liquid crystal display device 300.

Meanwhile, the timing controller 40 responds to the color signal RGB, the horizontal synchronizing signal H_SYNC, the vertical synchronizing signal V_SYNC, and the clock signal MCLK provided from the graphic controller 410 of the computer main body 400. The control signals required by the gate driving circuit 320 and the source driving circuit 330 are generated. In addition, the timing controller 350 selects one of the lamps 364 and 366 in the backlight unit 360 in response to the screen size control signal CTL_SIZE provided from the graphic controller 410, and the switching transistors. Generates a selection signal SEL for controlling (SW1-SW4). Operation of the liquid crystal display apparatus 300 according to the input of the screen size control signal CTL_SIZE is as follows.

FIG. 5 is a block diagram illustrating the backlight unit 360 illustrated in FIG. 3. Referring to FIG. 5, the inverter 362 of the backlight unit 360 converts the DC power V provided from the power supply unit 370 into an AC voltage of about 1000 to 1500V. The current I output from the inverter 362 is provided to the first lamp 364 and the second lamp 366, and the switch 367 is applied to the selection signal SEL output from the timing controller 350. In response, the current I output from the inverter 362 is selectively provided to the second lamp 366.

FIG. 6 is a flowchart illustrating operations of the graphic controller 410 and the liquid crystal display unit 300 illustrated in FIG. 4 according to a user's display mode selection. 7A and 7B illustrate examples of displaying an image on the LCD panel 310 according to a user's display mode selection. First, referring to FIG. 6, when the user operates the key input unit 420 of the computer main body 400 to select one of the reduced display mode and the normal display mode in step S500, the graphic controller 410 in step S510. Determines the mode selected by the user. If the result of the determination is that the normal display mode is selected, the procedure proceeds to step S511 and outputs a screen size control signal CTL_SIZE of a level (for example, a high level) corresponding to the normal display mode, and displays on the liquid crystal display device 300. The video signal to be converted is converted into a signal suitable for the normal display mode selected by the user and output.

In operation S512, the timing controller 350 of the liquid crystal display device 300 outputs a high level selection signal SEL. Subsequently, in step S513, as the switch 367 of the backlight unit 360 is turned on in response to the high level selection signal SEL, the current I output from the inverter 362 is first and second. It is provided with two lamps 364 and 366 so that the first and second lamps 366 and 366 are both on. In operation S514, all of the switching transistors SW1-SW4 are turned on in response to the high level selection signal SEL, so that all the thin film transistors T1 of the liquid crystal panel 310 are turned on. In the next step S515, the liquid crystal display device 300 displays an image on the entire liquid crystal panel 310 in response to the signals RGB, H_SYNC, V_SYNC, and MCLK provided from the graphic controller 410 (see FIG. 7A). ).

As a result of determining the mode selected by the user in step S510, if the reduced display mode is selected, the procedure proceeds to step S521 to display a screen size control signal CTL_SIZE of a level (for example, a low level) corresponding to the reduced display mode. The image signal to be displayed on the liquid crystal display device 300 is converted into a signal suitable for the reduced display mode selected by the user, and output.

In operation S522, the timing controller 350 of the liquid crystal display device 300 outputs a low level selection signal SEL. In a next step S523, as the switch 367 of the backlight unit 36 is turned off in response to the low level selection signal SEL, the current I output from the inverter 362 is the first lamp 364. ) Only the first lamp 366 is turned on. In operation S524, all of the switching transistors SW1-SW4 are turned off in response to the low level selection signal SEL, so that the j th to n th of the thin film transistors T1 of the liquid crystal panel 310 are turned off. The thin film transistors connected to the gate lines Gj-Gn and the thin film transistors connected to the first to mth data lines D1 to Dm are turned off. Therefore, in step S525, the liquid crystal display device 300 displays an image on a portion of the liquid crystal panel 310 in response to the signals RGB, H_SYNC, V_SYNC, and MCLK provided from the graphic controller 410 (FIG. 7B). Reference).

For example, when 1024x768 pixels are arranged in the liquid crystal panel 310, the pixels connected to the 0th to 599th gate lines G0-G299 are disposed in the first region 302A of the liquid crystal panel 310. The pixels connected to the gate lines G599 to G768 of the 599 th to 768 th belong to the second region 302B of the liquid crystal panel 310. On the other hand, the switching transistors SW3-SW4 are arranged between the 799th data line D799 and the 800th data line D800 to connect the pixels connected to the 800th and subsequent data lines with the gate lines G0-Gn. Optionally connect each one. In this case, in the normal display mode, the thin film transistors respectively configured in the 1024x768 pixels are turned on. In the reduced display mode, the thin film transistors respectively configured in the 800x600 pixels from the upper left of the liquid crystal panel 310 are turned on. And the thin film transistors of the remaining pixels are turned off. Therefore, power consumption in an area where no image is displayed can be prevented. However, it is obvious that the area in which the image is displayed in the reduced display mode may be variously changed by the producer or the user. In this embodiment, the liquid crystal panel 310 is horizontally divided so that the upper region is the first region 302A and the lower region is the second region 302B. However, the liquid crystal panel 310 is vertically divided. In this case, the left area may be allocated to the first area and the right area to the second area.

Meanwhile, when the computer main unit 400 receives power from the battery 440 and operates the computer main unit 400 and the liquid crystal display device 300, the operation of the computer main unit 400 is as follows. The control unit 430 of the computer main unit 400 receives battery remaining amount information (for example, voltage and current) output from the battery 440, calculates the remaining amount of the battery 440, and stores the battery 400. If it is determined that the remaining amount is lower than the reference level, a warning signal is output to the graphic controller 410. When the warning signal is input from the controller 430, the graphic controller 410 outputs a screen size control signal CTL_SIZE for reducing the size of the display screen, and displays an image signal to be displayed on the liquid crystal display device 300. The signal is converted into a signal suitable for display in a part of the first area 302A and output. When the remaining amount of the battery 400 is lower than the reference level, the operation of the liquid crystal display apparatus 300 operates in the same manner as when the user selects the reduced display mode, and thus description thereof will be omitted.

As described above, the liquid crystal display device 300 according to the present invention corresponds to the first area 302A of the liquid crystal panel 310 when the reduced display mode is selected by the user or the battery level is lower than the reference level. Since only the first lamp 364 is turned on and the second lamp 366 corresponding to the second area 302B is turned off, an image is displayed only in a predetermined area of the first area 302A, thereby reducing power consumption. In particular, while the computer system is powered from the battery, when the battery level is lower than the reference level, the screen size is automatically reduced to reduce the power consumption has the advantage of extending the battery life.

As mentioned above, preferred embodiments of the present invention are disclosed for the purpose of illustration, and those skilled in the art can improve and change various other embodiments within the spirit and technical scope of the present invention disclosed in the appended claims below. , Replacement or addition would be possible.

The liquid crystal display device of the present invention as described above divides the liquid crystal panel into first and second regions, and includes two lamps corresponding to the first and second regions, respectively, so that both lamps are turned on in the normal display mode. In this case, the image is displayed in both the first and second regions of the second liquid crystal panel, but in the reduced display mode, only the lamp corresponding to the first region of the liquid crystal panel is turned on, and then the image is displayed only in a part of the first region. Therefore, it is a very useful invention that can significantly reduce the power consumed in the lamp.

Claims (8)

In the liquid crystal display device, Using a first lamp corresponding to the first region of the liquid crystal panel and a second lamp corresponding to the second region other than the first region as a light source, to provide planar light of uniform brightness to the liquid crystal panel Back light; A backlight control unit for selectively turning on / off the first and second lamps according to a remaining battery state; And When only the first lamp is turned on, a screen having a size corresponding to the first area is displayed. When both the first and second lamps are turned on, a screen having a size corresponding to the first and second areas is displayed. The liquid crystal display device which can reduce the size of the display screen characterized by including the liquid crystal panel which is displayed. The method of claim 1, The backlight driving circuit, And when the user key input corresponds to the reduced display mode, driving the first lamp only. The method of claim 1, The backlight driving circuit, And when the user key input corresponds to a normal display mode, driving the first and second lamps together to reduce the size of the display screen. The method of claim 1, The backlight driving circuit, And driving only the first lamp when a signal indicating that the battery level is lower than a reference level is input from the host. The method according to claim 2 or 4, While only the first lamp is driven, the video signal provided from the host is And a video signal to be displayed on the entirety of the liquid crystal display panel is converted into a video signal suitable for display in the first area of the display panel. The method of claim 1, When the liquid crystal panel is divided horizontally, the liquid crystal display device can reduce the size of the display screen, characterized in that the upper region is the first region and the lower region is the second region. The method of claim 1, And dividing the liquid crystal panel vertically, wherein the left area is the first area and the right area is the second area. In the method for reducing the size of the display screen of the liquid crystal display device, Inputting a display mode selection key; Determining whether the display mode selection key corresponds to a reduced display mode; And As a result of the determination, when the display mode selection key corresponds to the reduced display mode, the first lamp corresponding to the first area of the liquid crystal display device is turned on, and a screen having a size corresponding to the first area is displayed. And turning off the second lamp corresponding to the two regions, wherein the size of the display screen of the liquid crystal display device is reduced.